水温、饲料蛋白及其互作效应对吉富罗非鱼生长与血清能源物质的影响

Effect of water temperature,dietary protein levels and their interaction on growth and serum energetic compounds in GIFT tilapia juvenile, Oreochromis niloticus(L.)

采用中心复合实验设计和响应曲面分析方法,在实验室条件下,探讨了温度（20~34℃）、饲料蛋白水平（25%~50%）及其互作效应对吉富罗非鱼（Oreochromis niloticus）幼鱼生长、饲料效率与血清能源物质（葡萄糖、甘油三酯和总蛋白）的影响。整个实验持续8周。结果表明,温度与饲料蛋白水平的一次效应对特定生长率和饲料效率有显著影响（P0.05）。温度与饲料蛋白水平的互作效应对饲料效率、血清葡萄糖、甘油三酯和总蛋白有显著影响（P＆lt;0.05）。温度对生长、饲料效率和血清甘油三脂与总蛋白水平的影响较饲料蛋白明显,而对血清葡萄糖的效应则与之相反。因子与特定生长率、饲料效率、血清葡萄糖、甘油三酯及总蛋白水平这5项响应值间二次多项回归方程的决定系数分别达到0.958、0.955、0.971、0.977和0.870（P＆lt;0.01）,可用于预测。综合以上实验结果,温度/饲料蛋白水平最优组合为29.9℃/40.3%,此时,特定生长率和饲料效率均较高,分别为2.748%/d和0.775,其可靠性达0.888。不同饲料蛋白水平下,水温对吉富罗非鱼血清代谢物质的影响也不同,增加水温有助于更好地利用饲料蛋白,提高血清中蛋白的分解与转化。

We evaluated the combined effect of temperature（20–34℃） and dietary protein level（25%.50%） on growth and serum glucose,triglyceride,and total protein levels in GIFT tilapia juveniles.We used a central composite rotatable experimental design and response surface methodology.The entire experiment lasted for 8 weeks. The linear effects of temperature,dietary protein level on growth and feed utilization were statistically significant（P0.05）.High temperatures and high dietary protein levels inhibited specific grouth rat（SGR） and feed efficiency（FE）.The linear effects of water temperature on serum glucose,triglyceride,and total protein levels were statistically significant（P0.05）.At a dietary protein level of 37.5%,serum glucose levels increased gradually as water temperature increased,whereas serum triglyceride and total protein levels decreased at the beginning and increased thereafter.The linear effect of dietary protein levels on serum glucose levels was significant（P0.05）;but the linear effect on serum triglyceride and total protein levels was insignificant（P0.05）.The reciprocal effects of temperature×dietary protein levels on FE,serum glucose,triglyceride,and total protein levels were significant（P0.05）.SGR,FE,serum triglyceride,and total protein levels were influenced more by temperature than by dietary protein levels.However,the pattern was reversed for serum glucose levels.Using our data,we developed a model to describe the effect of temperature and dietary protein level on serum glucose,triglyceride and total protein levels.The coefficients of determination were 0.958,0.955,0.971,0.977,and 0.870,respectively（P0.01）, and could be applied in projection.The optimal temperature/dietary protein level combination,obtained using a statistical optimization approach,was 29.9℃/ 40.3%,at which the maximal SGR and FE were 2.748%/d and 0.775 respectively,with the desirability being 0.888.The respective effects of water temperature on serum glucose, triglyceride,and total protein levels were observed under different dietary protein levels.Increased water temperature contributes to the better use of dietary protein,and an increase in serum protein catabolism and conversion.